U.S. patent application number 09/739346 was filed with the patent office on 2002-06-20 for apparatus and method for forming a tube having an article attached thereto.
Invention is credited to Brereton, Neil, Mason, Murray R..
Application Number | 20020073526 09/739346 |
Document ID | / |
Family ID | 24971859 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020073526 |
Kind Code |
A1 |
Mason, Murray R. ; et
al. |
June 20, 2002 |
Apparatus and method for forming a tube having an article attached
thereto
Abstract
In the present invention, at least one tubular blank and at
least one article such as a metal stamping, to be attached to a
hydroformed part, are loaded into a die. The tube is hydroformed
using typical methods. The article is positioned in the die such
that, when the tube is hydroformed, the final hydroformed tube
contacts the article at least at a point. Attachment means, such as
a laser welder, are provided with access to the contact point
between the article and the hydroformed tube so that a tack weld or
other attachment can be made between the article and the
hydroformed tube while still in the closed die. The hydroformed
tube and attached article are then removed as a joint assembly from
the die.
Inventors: |
Mason, Murray R.; (Bolton,
CA) ; Brereton, Neil; (Aurora, CA) |
Correspondence
Address: |
Todd D. Bailey
Bereskin & Parr
Box 401
40 King Street West
Toronto
ON
M5H 3Y2
CA
|
Family ID: |
24971859 |
Appl. No.: |
09/739346 |
Filed: |
December 19, 2000 |
Current U.S.
Class: |
29/421.1 ;
29/559 |
Current CPC
Class: |
B21D 26/047 20130101;
Y10T 29/49622 20150115; B23K 26/22 20130101; B23K 26/0093 20130101;
B23K 2101/006 20180801; Y10T 29/49805 20150115; Y10T 29/49998
20150115; B21D 26/035 20130101; Y10T 29/4994 20150115; B23K 37/0435
20130101 |
Class at
Publication: |
29/421.1 ;
29/559 |
International
Class: |
B23P 017/00; B23Q
007/00 |
Claims
We claim:
1. An apparatus for hydroforming at least one tubular blank
comprising: (a) a closeable die having at least one cavity therein
for confining at least one tubular blank, said die being adapted to
receive at least one article and position said at least one article
substantially in contact with said at least one tubular blank at at
least one contact point; and (b) pressurizing means for internally
pressurizing said at least one tubular blank to a desired pressure,
said closeable die being adapted to permit access to said at least
one contact point while said die is in a closed condition so that
said at least one article may be attached to said at least one
tubular blank when said die is closed.
2. The apparatus of claim 1 wherein said closeable die has at least
one passageway adapted to permit said access to said at least one
contact point.
3. The apparatus of claim 2 wherein said at least one passageway is
adapted to permit said at least one article to be welded to said at
least one tubular blank.
4. The apparatus of claim 1 wherein said closeable die further
comprises at least one recess for receiving and positioning said at
least one article in said die.
5. An apparatus for hydroforming at least one tubular blank
comprising: (a) a die having at least one cavity therein for
confining at least one tubular blank, said die adapted to receive
at least one article for attachment to said at least one tubular
blank; (b) pressurizing means for internally pressurizing said at
least one tubular member to a desired pressure; and (c) attachment
means for attaching said at least one article to said at least one
tubular blank, wherein said die and said attachment means are
adapted to permit said at least one article to be attached to said
at least one tubular blank when said at least one blank is disposed
in said at least one cavity.
6. The apparatus of claim 5 wherein said die and said attachment
means are adapted to permit said at least one article to be
attached to said at least one tubular blank when said at least one
blank is confined in said at least one cavity.
7. The apparatus of claim 5 wherein said die and said attachment
means are adapted to permit said at least one article to be
attached to said at least one tubular blank when said die is in a
closed condition.
8. The apparatus of claim 5 wherein said die further comprises a
passageway adapted to permit said attachment means to attach said
at least one article to said at least one tubular blank while said
at least one blank is confined in said at least one cavity.
9. The apparatus of claim 5 wherein said attachment means is
selected from the group comprising a welding apparatus, a soldering
apparatus, a brazing apparatus, a riveting apparatus and an
adhesive-applying apparatus.
10. The apparatus of claim 5 wherein said die further comprises at
least one recess for receiving and positioning said at least one
article in said die.
11. A method for hydroforming at least one tubular member
comprising the steps of: (a) placing at least one tubular blank in
at least one cavity defined in a die, said at least one cavity
having an internal surface corresponding to a desired configuration
of a final tubular member, said at least one tubular blank having
an internal chamber and a wall; (b) placing at least one article in
said die; (c) confining said at least one tubular blank and said at
least one article in said die; (d) sealing said internal chamber;
(e) pressurizing said internal chamber so as to cause said at least
one blank to conform to said internal surface of said at least one
cavity to create said at least one tubular member; (f) contacting
said at least one article with said wall of said at least one
tubular member; and (g) attaching said at least one article to said
wall of said at least one tubular member.
12. The method of claim 11 wherein step (g) is achieved by
welding.
13. The method of claim 11 wherein step (g) is performed before
said at least one tubular member is released from said die.
14. The method of claim 11 wherein step (g) is performed after said
die is opened.
15. The method of claim 11 wherein said at least one article has at
least one flat surface for connection to said at least one tubular
member.
16. The method of claim 11 wherein step (g) is performed before
step (e).
17. The method of claim 11 wherein steps (b) and (f) are performed
together.
18. The method of claim 11 further comprising the step of changing
the shape of said at least one article when said at least one
article is confined in said die.
Description
FIELD OF THE INVENTION
[0001] This invention relates to hydroforming a tube and, more
particularly, to forming a tube with an article attached
thereto.
BACKGROUND OF THE INVENTION
[0002] Hydroforming is well known for its ability to form an
integral hollow beam with a complex shape, something which would
otherwise have to be fabricated from several pieces and/or bent to
shape. Typically, a round tubular blank is inserted between a pair
of dies which have an internal cavity in the form of the desired
exterior shape of the final part. Then the ends of the tube are
plugged and the interior chamber of the tubular blank is
pressurized, generally with water or hydraulic fluid, to force it
into the shape of the die cavity. The completed part is then
de-pressurized and removed.
[0003] The hydroformed part often, in its final application,
requires that one or more articles be attached to it. For example,
hydroformed components are used in making subframe assemblies in
automobiles, such as shown in FIG. 1. The subframe assembly A often
have metal stampings S and cross-member C welded thereto to form
the subframe assembly and permit the subframe assembly to be
fastened to a frame assembly. To accomplish this, typically once
the tube T has been hydroformed, it is removed from the die and
placed in a welding jig, along with metal stampings S, so that a
welding machine can weld stampings S to tube T to yield hydroformed
assembly A. However, these additional fitting and welding steps add
process cost and time, and also have a tendency to introduce errors
such as additional dimensional variation or missed process steps,
both of which can be detrimental to the function and economics of
the part.
[0004] Referring to U.S. Pat. No. 5,845,382 to Schultz et al., it
is known in the manufacturing of a seat frame assembly to position
a hollow cylindrical part in a die and circumferentially around a
tube to be hydroformed prior to hydroforming, and then hydroforming
the tube to expand it outwardly to integrally engage the outer
cylindrical to effectively lock the pieces together. While this
technique does limit the requirement for additional assembly and
welding steps, its application is limited to situations where the
article to be circumferentially attached surrounds the hydroformed
part.
[0005] Accordingly, there is a need for an improved method and
apparatus for attaching an article to a hydroformed tube which can
decrease process costs and time, as well as increase the accuracy
and repeatability with which mass produced parts are
fabricated.
SUMMARY OF THE INVENTION
[0006] In one aspect, the present invention provides an apparatus
for hydroforming at least one tubular blank comprising a closeable
die having at least one cavity therein for confining at least one
tubular blank, the die being adapted to receive at least one
article and position the at least one article substantially in
contact with the at least one tubular blank at at least one contact
point, and pressurizing means for internally pressurizing the at
least one tubular blank to a desired pressure, the closeable die
being adapted to permit access to the at least one contact point
while the die is in a closed condition so that the at least one
article may be attached to the at least one tubular blank when the
die is closed.
[0007] In a second aspect, the present invention provides an
apparatus for hydroforming at least one tubular blank comprising a
die having at least one cavity therein for confining at least one
tubular blank, the die adapted to receive at least one article for
attachment to the at least one tubular blank, pressurizing means
for internally pressurizing the at least one tubular member to a
desired pressure, and attachment means for attaching the at least
one article to the at least one tubular blank, wherein the die and
the attachment means are adapted to permit the at least one article
to be attached to the at least one tubular blank when the at least
one blank is disposed in the at least one cavity.
[0008] In a third aspect, the present invention provides a method
for hydroforming at least one tubular member comprising the steps
of placing at least one tubular blank in at least one cavity
defined in a die, the at least one cavity having an internal
surface corresponding to a desired configuration of a final tubular
member, the at least one tubular blank having an internal chamber
and a wall, placing at least one article in the die, confining the
at least one tubular blank and the at least one article in the die,
sealing the internal chamber, pressurizing the internal chamber so
as to cause the at least one blank to conform to the internal
surface of the at least one cavity to create the at least one
tubular member, contacting the at least one article with the wall
of the at least one tubular member, and attaching the at least one
article to the wall of the at least one tubular member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a better understanding of the present invention, and to
show more clearly how it may be carried into effect, reference will
now be made by way of example to the accompanying drawings.
[0010] The drawings show articles made according to a preferred
embodiment of the present invention, in which:
[0011] FIG. 1 is an exploded isometric view of an automobile
subframe assembly;
[0012] FIG. 2 is a sectional side view of a hydroforming die set
according to the present invention; and
[0013] FIG. 3 is an exploded isometric view of another automobile
subframe assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Hydroforming presses and dies are well known in the art and
thus it is necessary only to describe such equipment briefly here.
Referring to FIG. 2, a hydroforming apparatus according to the
present invention is shown generally at 10. Apparatus 10 has a
first die half 12 a second die half 14 and a slide 16 which
cooperate to form an interior cavity 18 having an internal surface
20. The shape of internal surface 20 is one which is desired as the
final shape for a tubular blank (not shown), having an internal
chamber (not shown), to be formed in cavity 18 to yield tubular
member 22, as will described in more detail below. A pair of
recesses 24 are provided in die halves 12 and 14, each for
receiving a pair of articles 26 for attachment to tubular member 22
according to the present invention. A pair of locating pins 28 are
provided in die halves 12 and 14 for positioning and holding
articles 26 in position, as described below. Die halves 12 and 14
each have a passageway 30 which provides access to an attachment
point 32 between each article 26 and tubular member 22.
[0015] In use, a tubular blank (not shown) is positioned in cavity
18 in die half 12 and articles 26 are placed in recesses 24.
Locating pins 28 are positioned to hold articles 26 in position
against slide 16. Die halves 12 and 14 are closed and the tubular
blank (not shown) is pressurized to cause tubular member 22 to be
formed against internal surface 20 of cavity 18 and against
articles 26. The closing pressure of die halves 12 and 14 may also
form articles 26, as desired, and the shape of tubular member 22
may conform locally around articles 26, thereby permitting tubular
member 22 to receive articles 26 so as to provide a close fit
between them.
[0016] After hydroforming, a laser weld is provided through
passages 30 to tack weld articles 26 to tubular member 22. The
internal pressure in tubular member 22 is released and die halves
12 and 14 are opened to yield the assembled part which may then be
further processed (if required) to strengthen the connection
between articles 26 and tubular member 22.
[0017] Referring again to FIG. 1, present invention permits
articles such as bracket stampings "S" to be assembled onto a
hydroformed tubular member "T" more or less simultaneously with the
hydroforming process. Advantageously, this reduces the number of
steps required in fabricating parts having hydroformed components
and increases the repeatability and dimensional accuracy of the
final part.
[0018] While the above description constitutes the preferred
embodiment, it will be appreciated that the present invention is
susceptible to modification and change without departing from the
fair meaning of the accompanying claims.
[0019] For example, referring to FIG. 3, one skilled in the art
will understand that more than one part, such has tubes T.sub.1 and
T.sub.2, may be hydroformed in apparatus 10. Also, one skilled in
the art will understand that articles 26 need not be flat articles
or a stamping, but may have any shape and formed by any process and
made from any desirable material.
[0020] Also, the means by which the articles are attached to the
tubular member in the die is not critical to the present invention,
and laser welding need not necessarily be used. Other types of
welding, or an adhesive, or other temporary or permanent fastening
means may be employed, such as chemical bonding agents like glue,
other mechanical means such as riveting, brazing or soldering.
Still other fastening means may be employed.
[0021] Further, attachment need not be done while the dies are
closed, but may be done after the dies are opened. Attachment may
be done while hydroforming pressure is maintained in tubular member
22, or the pressure may be varied or may be released
altogether.
[0022] The present invention may be employed with any known
hydroforming technique and may be used with low-pressure
hydroforming and with high-pressure hydroforming techniques. It
will be understood that the particular means of hydroforming
tubular member 22 is not important to the present invention and,
further, that the tubular member need not be formed at all in the
cavity, but rather its initial shape may be maintained.
Non-cylindrical blank may also be used.
[0023] Still other modifications may be apparent to those skilled
in the art but these are not intended to depart from the scope of
the appended claims. It will be understood in the claims that the
step of pressurizing the internal chamber of the blank may be
performed either before or after the step of confining the blank in
the die cavity.
* * * * *